Fluid identification method and device based on energy difference and medium

Abstract

The invention provides a fluid identification method and device based on energy difference and a medium, and belongs to the field of geophysical exploration. The method comprises the following steps: S100, inputting a CRP gather and average speed data Vstk; s200, extracting an angle gather according to the input CRP gather and the average velocity data Vstk; s300, extracting partial superposition data volumes of the large angle, the medium angle and the small angle; s400, time channel sets of the three angles are calculated; s500, extracting discrete energy bodies of a low-frequency band and a high-frequency band of the three-angle partial superposition data; and S600, extracting an energy difference attribute data body. According to the method, the difference between the near trace and the far trace of the stratum containing oil and gas and the change between low-frequency band and high-frequency band attributes are considered, energy or attributes of different incident angles and different frequency bands are extracted based on the angle partial superposition data, and the method can be used for developing seismic fluid identification research.

Description

Technical Field

[0001] This invention belongs to the field of geophysical exploration, specifically relating to a fluid identification method, device, and medium based on energy differences. Background Technology

[0002] Seismic acquisition utilizes artificial seismic sources to generate seismic wavelets. When these wavelets propagate underground, they encounter interfaces with differences in formation impedance, resulting in transmission and reflection. Geophones placed on the surface or in wells receive these underground seismic signals. Through processing and imaging techniques, migrated and repositioned CRP gathers or post-stack seismic data can be obtained. Seismic profiles contain rich amplitude and travel time information, and the energy attenuation caused by seismic waves during propagation is also hidden within the seismic signal. Seismic wave attenuation can be classified into two types: one is attenuation related to the propagation characteristics of the seismic waves, with greater attenuation in shallow layers and less so in deeper layers; the other is intrinsic attenuation related to the propagation medium, such as absorption attenuation caused after passing through oil and gas-bearing formations. The characteristics of the second type of attenuation can be used to detect the oil and gas content of formations. Researchers have studied various fluid identification methods based on the attenuation characteristics of seismic waves after passing through oil and gas-bearing formations, mainly divided into pre-stack and post-stack methods. Attributes extracted from post-stack seismic data, such as "sweet spots," absorption coefficients, attenuation gradients, "bright spots," frequency attenuation, or "low-frequency shadows," can be used for fluid detection in different types of reservoirs. Post-stack fluid identification technology is simple and fast to apply, but its effectiveness is greatly affected by reservoir type. Techniques such as AVO attribute analysis, pre-stack elastic parameter inversion, and frequency-varying AVO inversion based on pre-stack data can also be used for fluid identification. Pre-stack fluid identification technology extracts richer parameters and has a stronger ability to solve practical problems. However, pre-stack inversion technology has a complex process, involving steps such as seismic horizon calibration, angle wavelet extraction, rock physics modeling, seismic inversion modeling, and seismic inversion. It also has a large computational load, a long application cycle, and a high technical threshold. Summary of the Invention

[0003] The purpose of this invention is to solve the problems existing in the prior art and provide a fluid identification method, device and medium based on energy difference. Based on the angular part of the incident angle superimposed data, it makes full use of the energy difference of different incident angles and different frequency bands to construct an attribute that can be used for fluid identification. The calculation steps are simple and can improve the detection capability of fluid identification.

[0004] This invention is achieved through the following technical solution:

[0005] A first aspect of the present invention provides a fluid identification method based on energy differences, comprising:

[0006] S100, Input CRP gather and average velocity data V stk ;

[0007] S200, based on the input CRP gather and average velocity data V stk Extract angle gathers;

[0008] S300 extracts the superimposed data volume from three angles: large, medium, and small.

[0009] S400, calculates the time channel set from three angles;

[0010] S500 extracts discrete energy volumes from the low-frequency and high-frequency bands of the superimposed data from three angles.

[0011] S600, extracts energy difference attribute data volume.

[0012] A further improvement of the present invention is that:

[0013] S200 extracts angle gathers based on the input CRP gathers and average velocity. Specific operations include:

[0014] For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula:

[0015]

[0016] Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

[0017] A further improvement of the present invention is that:

[0018] S400 calculates the time channel set for three angles. Specific operations include:

[0019] High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

[0020] A further improvement of the present invention is that:

[0021] The S500 extracts the discrete energy volumes of the low-frequency and high-frequency bands from the superimposed data volume of three angles. Specific operations include:

[0022] Define the frequency ranges of the low-frequency band and the high-frequency band;

[0023] Based on the defined frequency ranges of the low-frequency and high-frequency bands, the discrete energy volumes (Dis) of the low-frequency and high-frequency bands of the three-angle part superimposed data volume are extracted. min-low Dis min-high Dis mid-low Dis mid-high Dis max-low and Dis max-high ;

[0024] Among them, Dis min-low Dis is a small-angle, low-frequency discrete energy source. min-high Dis is a discrete energy source with a small angle and high frequency band. mid-low As a discrete energy source in the mid-angle low-frequency band, Dis mid-high Dis is a discrete energy source in the mid-angle, high-frequency band. max-low As a large-angle, low-frequency discrete energy source, Dis max-high It is a discrete energy body with a large angle and high frequency band.

[0025] A further improvement of the present invention is that:

[0026] S600, extracting energy difference attribute data volume, specific operations include:

[0027] The energy difference attribute at each location in three-dimensional space is calculated using the following formula:

[0028] EnVar (i,j,k) =0.5*[(Dis(i,j,k)] min-high -Dis(i,j,k) min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )]

[0029] -0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )]

[0030] Where (i,j,k) are the position coordinates in three-dimensional space.

[0031] A second aspect of the present invention provides a fluid identification device based on energy differences, comprising:

[0032] Input unit, used to input CRP gather and average velocity data V stk ;

[0033] Angle gather extraction unit, used to extract angles from input CRP gathers and average velocity data V.stk Extract angle gathers;

[0034] The partial superimposed data volume extraction unit is used to extract partial superimposed data volumes from three angles: large, medium, and small.

[0035] The time channel set calculation unit is used to calculate the time channel set from three angles;

[0036] Discrete energy volume extraction unit is used to extract discrete energy volumes of low-frequency and high-frequency bands from the superimposed data of three angles;

[0037] The energy difference attribute extraction unit is used to extract the energy difference attribute data volume.

[0038] A further improvement of the present invention is that:

[0039] The angle gather extraction unit performs the following operations:

[0040] For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula:

[0041]

[0042] Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

[0043] A further improvement of the present invention is that:

[0044] The time channel set calculation unit specifically performs the following operations:

[0045] High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

[0046] A further improvement of the present invention is that:

[0047] The energy difference attribute extraction unit performs the following operations:

[0048] The energy difference attribute at each location in three-dimensional space is calculated using the following formula:

[0049] EnVar (i,j,k) =0.5*[(Dis(i,j,k)] min-high -Dis(i,j,k)min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )]

[0050] -0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )]

[0051] Where (i,j,k) are the position coordinates in three-dimensional space.

[0052] A third aspect of the present invention provides a computer-readable storage medium storing at least one computer-executable program, which, when executed by the computer, causes the computer to perform the steps in the energy difference-based fluid identification method.

[0053] Compared with the prior art, the beneficial effects of the present invention are:

[0054] After a formation contains oil and gas, the amplitude of vibrations at different offset distances will differ, which is the AVO response characteristic. At the same time, due to the absorption effect of the fluid, the energy at high and low frequencies will also differ. The energy difference attribute proposed in this invention integrates the energy difference at near, medium and far angles (i.e., AVO response characteristics) with the energy difference in the low and high frequency bands (absorption attenuation characteristics), which is beneficial to improving the accuracy of fluid identification.

[0055] This invention takes into account the differences between near-channel and far-channel after formation contains oil and gas, as well as the changes between low-frequency and high-frequency attributes. Based on the angular partial superposition data, it extracts energy or attributes of different incident angles and frequency bands, and constructs a new energy difference attribute, which can be used to carry out seismic fluid identification research. Attached Figure Description

[0056] Figure 1 This is a flowchart of a fluid identification method based on energy differences in an embodiment of the present invention. Detailed Implementation

[0057] The present invention will now be described in further detail with reference to the accompanying drawings:

[0058]

Example 1

[0059] This invention provides a fluid identification method based on energy differences. It extracts energy differences at different angles and frequency bands from angularly superimposed data, and can be used for seismic fluid identification research. Figure 1 As shown, the specific implementation steps include, but are not limited to, the following steps:

[0060] S100, Input CRP gather and average velocity data V stk ;

[0061] S200, based on the input CRP gather and average velocity data V stk Extract angle gathers;

[0062] S300 extracts the superimposed data volume from three angles: large, medium, and small.

[0063] S400, calculates the time channel set from three angles;

[0064] S500 extracts discrete energy volumes from the low-frequency and high-frequency bands of the superimposed data from three angles.

[0065] S600, extracts energy difference attribute data volume.

[0066] This invention takes into account the differences between near-channel and far-channel after formation contains oil and gas, as well as the changes between low-frequency and high-frequency attributes. Based on the angular partial superposition data, it extracts energy or attributes of different incident angles and frequency bands, and constructs a new energy difference attribute, which can be used to carry out seismic fluid identification research.

[0067]

Example 2

[0068] S200 extracts angle gathers based on the input CRP gathers and average velocity. Specific operations include:

[0069] For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula:

[0070]

[0071] Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

[0072]

Example 3

[0073] S300 extracts the overlay data volume from three angles: large, medium, and small. Specific operations include:

[0074] Based on the actual situation and application requirements of the Daoji, partial superimposed data volumes PS at small, medium, and large angles were extracted respectively. min PS mid and PS max .

[0075] For example, extracting a 5° portion of the stacked data volume can stack seismic signals from 0° to 10° in the angle gather; extracting a 15° portion of the stack can stack seismic signals from 11° to 20° in the angle gather; and extracting a 25° portion of the stack can stack seismic signals from 21° to 30° in the angle gather.

[0076] The angle value can be determined based on the effective angle range of the target layer.

[0077]

Example 4

[0078] S400 calculates the time channel set for three angles. Specific operations include:

[0079] High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

[0080] There are many methods for time-frequency decomposition of seismic signals, such as WVD, short-time Fourier transform, wavelet transform, S-transform, generalized S-transform, and matching pursuit. Different algorithms have different time-frequency resolutions, and different time-frequency analysis methods can be selected according to requirements.

[0081]

Example 5

[0082] The S500 extracts the discrete energy volumes of the low-frequency and high-frequency bands from the superimposed data volume of three angles. Specific operations include:

[0083] Define the frequency ranges of the low-frequency band and the high-frequency band;

[0084] Based on the defined frequency ranges of the low-frequency and high-frequency bands, the discrete energy volumes (Dis) of the low-frequency and high-frequency bands of the three-angle part superimposed data volume are extracted. min-low Dis min-high Dis mid-low Dis mid-high Dis max-low and Dis max-high ;

[0085] Among them, Dis min-low For small-angle, low-frequency discrete energy sources, Dis min-high Dis is a discrete energy body with a small angle and high frequency band. mid-low As a discrete energy source in the mid-angle low-frequency band, Dis mid-high Dis is a discrete energy source in the mid-angle, high-frequency range. max-low As a large-angle, low-frequency discrete energy source, Dismax-high It is a discrete energy body with a large angle and high frequency band.

[0086] The low and high frequencies should be determined based on the instantaneous spectral characteristics of the target layer in the actual seismic data (specifically, the three frequency values ​​of low, medium, and high should be determined based on the instantaneous spectral range of the target layer). For example, if the dominant frequency of the instantaneous spectrum of the target layer is 30Hz, then the low frequency can be 20Hz and the high frequency can be 40Hz, depending on the specific circumstances.

[0087]

Example 6

[0088] S600, extracting energy difference attribute data volume, specific operations include:

[0089] The energy difference attribute at each location in three-dimensional space is calculated using the following formula:

[0090] EnVar (i,j,k) =0.5*[(Dis(i,j,k)] min-high -Dis(i,j,k) min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )]-0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )]

[0091] Where (i,j,k) are the position coordinates in three-dimensional space.

[0092] Using the above formula, the energy difference attribute of all coordinate points in three-dimensional space can be calculated, that is, the energy difference attribute volume EnVar can be obtained, and the energy difference attribute volume EnVar of the entire data volume Cube can be extracted.

[0093] The area with a large energy difference attribute EnVar is the fluid-sensitive zone.

[0094]

Example 7

[0095] This invention provides a fluid identification device based on energy differences, comprising:

[0096] Input unit, used to input CRP gather and average velocity data V stk ;

[0097] Angle gather extraction unit, used to extract angles from input CRP gathers and average velocity data V. stk To extract angle gathers, perform the following operations:

[0098] For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula:

[0099]

[0100] Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

[0101] The partial overlay data volume extraction unit is used to extract partial overlay data volumes from three angles: large, medium, and small. Specifically, it performs the following operations:

[0102] Based on the actual situation and application requirements of the Daoji, partial superimposed data volumes PS at small, medium, and large angles were extracted respectively. min PS mid and PS max .

[0103] The time channel set calculation unit is used to calculate the time channel set for three angles, and specifically performs the following operations:

[0104] High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

[0105] The discrete energy volume extraction unit is used to extract the discrete energy volume of the low-frequency and high-frequency bands of the superimposed data from three angles. Specifically, it performs the following operations:

[0106] Define the frequency ranges of the low-frequency band and the high-frequency band;

[0107] Based on the defined frequency ranges of the low-frequency and high-frequency bands, the discrete energy volumes (Dis) of the low-frequency and high-frequency bands of the three-angle part superimposed data volume are extracted. min-low Dis min-high Dis mid-low Dis mid-high Dis max-low and Dis max-high ;

[0108] Among them, Dis min-low For small-angle, low-frequency discrete energy sources, Dis min-high Dis is a discrete energy body with a small angle and high frequency band. mid-low As a discrete energy source in the mid-angle low-frequency band, Dis mid-highDis is a discrete energy source in the mid-angle, high-frequency range. max-low As a large-angle, low-frequency discrete energy source, Dis max-high It is a discrete energy body with a large angle and high frequency band.

[0109] The low and high frequencies should be determined based on the instantaneous spectral characteristics of the target layer in the actual seismic data (specifically, the three frequency values ​​of low, medium, and high should be determined based on the instantaneous spectral range of the target layer). For example, if the dominant frequency of the instantaneous spectrum of the target layer is 30Hz, then the low frequency can be 20Hz and the high frequency can be 40Hz, depending on the specific circumstances.

[0110] The energy difference attribute extraction unit is used to extract the energy difference attribute data volume, and specifically performs the following operations:

[0111] The energy difference attribute at each location in three-dimensional space is calculated using the following formula:

[0112] EnVar (i,j,k) =0.5*[(Dis(i,j,k)] min-high -Dis(i,j,k) min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )]

[0113] -0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )]

[0114] Where (i,j,k) are the position coordinates in three-dimensional space.

[0115] Using the above formula, the energy difference attribute of all coordinate points in three-dimensional space can be calculated, that is, the energy difference attribute volume EnVar can be obtained, and the energy difference attribute volume EnVar of the entire data volume Cube can be extracted.

[0116] The area with a large energy difference attribute EnVar is the fluid-sensitive zone.

[0117]

Example 8

[0118] This invention provides a computer-readable storage medium storing at least one computer-executable program, which, when executed by the computer, causes the computer to perform the steps in the energy difference-based fluid identification method.

[0119] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0120] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the technical solutions described in the specific embodiments of the present invention. Therefore, the foregoing description is only a preferred option and is not restrictive.

[0121] Any person skilled in the art to which this invention pertains may make any modifications and changes in form and details of implementation without departing from the spirit and scope disclosed herein, but the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A fluid identification method based on energy difference, characterized in that, include: S100, Input CRP gather and average velocity data V stk ; S200, based on the input CRP gather and average velocity data V stk Extract angle gathers; S300 extracts the superimposed data volume from three angles: large, medium, and small. S400, calculates the time channel set from three angles; S500 extracts discrete energy volumes from the low-frequency and high-frequency bands of the superimposed data from three angles. S600, extracts energy difference attribute data volume.

2. The method according to claim 1, characterized in that, S200 extracts angle gathers based on the input CRP gathers and average velocity. Specific operations include: For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula: Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

3. The method according to claim 1, characterized in that, S400 calculates the time channel set for three angles. Specific operations include: High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

4. The method according to claim 1, characterized in that, The S500 extracts the discrete energy volumes of the low-frequency and high-frequency bands from the superimposed data volume of three angles. Specific operations include: Define the frequency ranges of the low-frequency band and the high-frequency band; Based on the defined frequency ranges of the low-frequency and high-frequency bands, the discrete energy volumes (Dis) of the low-frequency and high-frequency bands of the three-angle part superimposed data volume are extracted. min-low Dis min-high Dis mid-low Dis mid-high Dis max-low and Dis max-high ; Among them, Dis min-low For small-angle, low-frequency discrete energy sources, Dis min-high Dis is a discrete energy body with a small angle and high frequency band. mid-low As a discrete energy source in the mid-angle low-frequency band, Dis mid-high Dis is a discrete energy source in the mid-angle, high-frequency range. max-low As a large-angle, low-frequency discrete energy source, Dis max-high It is a discrete energy body with a large angle and high frequency band.

5. The method according to claim 4, characterized in that, S600, extracting energy difference attribute data volume, specific operations include: The energy difference attribute at each location in three-dimensional space is calculated using the following formula: EnVar (i,j,k) =0.5*[(Dis(i,j,k) min-high -Dis(i,j,k) min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )] -0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )] Where (i,j,k) are the position coordinates in three-dimensional space.

6. A fluid identification device based on energy difference, characterized in that, include: Input unit, used to input CRP gather and average velocity data V stk ; Angle gather extraction unit, used to extract angles from input CRP gathers and average velocity data V. stk Extract angle gathers; The partial superimposed data volume extraction unit is used to extract partial superimposed data volumes from three angles: large, medium, and small. The time channel set calculation unit is used to calculate the time channel set from three angles; Discrete energy volume extraction unit is used to extract discrete energy volumes of low-frequency and high-frequency bands from the superimposed data of three angles; The energy difference attribute extraction unit is used to extract the energy difference attribute data volume.

7. The apparatus according to claim 6, characterized in that, The angle gather extraction unit specifically performs the following operations: For the input CRP gather and average velocity data V stk The angle gather (AngGather) is calculated using the following formula: Where θ is the angle value, x is the offset distance, and V stk The data represents the average speed, and t0 represents the travel time at the current moment.

8. The apparatus according to claim 6, characterized in that, The time channel set calculation unit specifically performs the following operations: High-precision time-frequency analysis was used to analyze the partial stacked data volume PS at three angles. min PS mid and PS max Perform time-frequency decomposition to obtain the time channel set TFG. min TFG mid and TFG max .

9. The apparatus according to claim 6, characterized in that, The energy difference attribute extraction unit specifically performs the following operations: The energy difference attribute at each location in three-dimensional space is calculated using the following formula: EnVar (i,j,k) =0.5*[(Dis(i,j,k) min-high -Dis(i,j,k) min-low ) / (Dis(i,j,k) mid-high -Dis(i,j,k) mid-low )] -0.5*[(Dis(i,j,k) mid-high -Dis(i,j,k) mid-low ) / (Dis(i,j,k) max-high -Dis(i,j,k) max-low )] Where (i,j,k) are the position coordinates in three-dimensional space.

10. A computer-readable storage medium storing at least one computer-executable program, which, when executed by the computer, causes the computer to perform the steps of the fluid identification method based on energy differences as described in any one of claims 1-5.

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